In the production of natural gas it is sometimes necessary to subject the raw natural gas stream to a purification process in order to produce natural gas with a sufficient combustibles content so that it may be efficiently used within a natural gas distribution network such as a pipeline system. A number of such natural gas purification systems are known and practiced commercially.
Methane, the main component of natural gas, is widely used as a chemical synthesis feedstock. As such, the methane must be of a high purity to ensure effective downstream synthesis. It would be highly desirable to produce high purity methane, suitable for use in subsequent chemical synthesis reactions, in conjunction with natural gas purification.
Accordingly, it is an object of this invention to provide a system which can process a raw natural gas feed stream and produce both fuel and high purity methane.
Conventional natural gas purification systems which process a nitrogen-containing raw natural gas stream typically produce pipeline quality natural gas having a significant nitrogen content such as up to five mole percent or more. While this is acceptable for most uses of the natural gas, such a nitrogen content cannot be tolerated in some applications, such as in certain metallurgical processes where nitrogen can cause detriment to the metal. Accordingly, it is another object of this invention to provide a system which can process a raw natural gas feed stream and produce both fuel and high purity natural gas.